1. Field of the Invention
This invention relates to a recording medium. In addition, this invention relates to a contents-data editing apparatus designed to make a playlist for instructing the playback of one or more selected from a plurality of contents of data stored in a recording medium. Furthermore, this invention relates to a method of updating a playlist.
2. Description of the Related Art
The word “content” used here means, for example, a home movie, a motion picture, a television program, an audio visual stream, or a music tune. Data representing one content is referred to as content data, while data representing a plurality of contents is referred to as contents data. Accordingly, contents data is composed of plural pieces representing respective contents.
In some cases, data representing many contents is recorded on a recording medium such as a DVD, a memory, or a hard disc. Generally, a playlist indicates one or more selected from such contents by a user as an object or objects to be played back. The playlist further indicates the order in which the selected contents should be played back.
Japanese patent application publication number 2002-158971 discloses a system designed so that an AV stream, as an entity of contents, is managed by ClipInformation and reproduction of the AV stream is managed by Playlist. Address information on discontinuity points in the AV stream, information associating the address information and time information in the AV stream with each other, and time information on a characteristic image in the AV stream are recorded in the ClipInformation as attribute information of the AV stream. In the system of Japanese application 2002-158971, a portion of a content data can be designated by a playlist.
Japanese patent application publication number 2005-196833 discloses an audio apparatus including a hard disc for storing music files and a management database, and a device for generating playlists and recording the generated playlists on the hard disc. Ones selected from the music files in the hard disc are registered in the playlists. A set of registered music files varies from playlist to playlist. There may be one or more registered music files common to at least two of the playlists. The music files in the hard disc are assigned serial ID numbers, respectively. The playlists in the hard disc are assigned different ID numbers, respectively. The management database is controlled to indicate the relation of each of the music files in the hard disc with a playlist or playlists in which the present music file is registered. Specifically, the management database holds the ID numbers of the music files in the hard disc. For each of the music-file ID numbers, the management database holds the ID number or numbers of a playlist or playlists in which the music file corresponding to the present music-file ID number is registered. Furthermore, the management database indicates the relation of each of the music files with an address on the hard disc at which the present music file starts.
In the audio apparatus of Japanese application 2005-196833, a music file can be deleted from a playlist or playlists. Specifically, the ID number of a target music file (a music file to be deleted) is derived. The management database is accessed in response to the derived music-file ID number to find a playlist or playlists in which the target music file is registered. Then, the target music file is deleted from the found playlist or playlists.
It is desirable that as content data or a file is edited, a related playlist or playlists are updated accordingly. When the number of the related playlists is relatively large, complicated and troublesome data processing tends to be required for updating the playlists.
An explanation is given of the case where content data stored in a recording medium is captured-image data generated by a video camera and relates with a plurality of playlists in the recording medium. When a later portion representative of wrong captured images is deleted from the content data, the related playlists are read from the recording medium. Regarding each of the read playlists, information about an on-recording-medium position at which the recorded region for the content data ends is updated in accordance with the foregoing deletion. Thus, as the number of the related playlists increases, it takes a considerably longer time to update the related playlists in harmony with the editing of the content data.